ESET says malware used to attack more than 500,000 computers daily

ESET, a provider of proactive digital protection, announced on March 18 that its security research team, in collaboration with CERT-Bund, the Swedish National Infrastructure for Computing and other leading agencies, has uncovered a widespread cybercriminal campaign involving a Backdoor Trojan which seized control of more than 25,000 UNIX servers worldwide.

Once infected, victims’ systems are used to steal credentials, re-direct Web traffic to malicious content and send as many as 35 million spam messages per day.

“Windigo has been gathering strength, largely unnoticed by the security community, for more than two and a half years and currently has 10,000 servers under its control,” said Pierre-Marc Bureau, security intelligence program manager at ESET. “This number is significant if you consider each of these systems have access to significant bandwidth, storage, computing power and memory.”

The attack, which has been dubbed Operation Windigo by security experts, hijacks servers, infects the computers that visit them and steals information from victims. The infected servers are then used to re-direct half a million Web visitors to malicious content on a daily basis. Servers located throughout the U.S., Germany, France and the UK are all among those infected.

With more than 60 percent of the world’s Web sites running on Linux servers, ESET researchers are warning Webmasters and system administrators to check their systems to see if they have been compromised. The company published a detailed technical report on March 18 presenting the findings of the teams’ investigations and malware analysis. The report also provides guidance on how businesses can determine if their systems are affected and instructions for removing the malicious code. Operating systems altered by the spam component include Linux, FreeBSD, OpenBSD, OS X and Windows.

If IT administrators discover their systems are infected, they are advised to wipe affected computers and re-install the operating system and software. For a higher level of protection in the future, technology such as two-factor authentication should be considered.

To download the full Operation Windigo report, readers can visit welivesecurity.com/windigo.